1. Field of the Invention
The present invention relates to an analysis apparatus and analysis method of chlorosilanes.
This application claims priority on Japanese Patent Application No. 2008-208211, filed on Aug. 12, 2008, the content of which is incorporated herein by reference.
2. Conventional Art
Chlorosilanes, such as trichlorosilane, tetrachlorosilane, and the like, are used for a raw material of polycrystalline silicon, a semiconductor, e.g., an epitaxial film of a silicon wafer, and a raw material of an optical fiber. In these applications, chlorosilanes with extremely low level of metal contaminations, namely, Fe, Ni, Cr, Al, Cu, Zn, and the like, are required. Further, samples of the chlorosilanes, which are almost free from an influence of these metal contaminations, are essential for evaluating qualities of the chlorosilanes.
As a conventional technique for analyzing chlorosilanes, the patent document 1 discusses a technique in which a chlorosilane solution is diluted with argon gas, and a high-frequency inductively-coupled plasma emission analysis method is used. Also the patent document 2 discusses a technique in which moisture in a silane gas is removed, and the silane gas is introduced to a discharge type photoionization detector through a predetermined device.
However, the chlorosilanes, which passed through no condensing process, are directly measured in the techniques discussed in these patent documents. Therefore, main components in a sample may often disturb a detection of the metal contaminations, and then high analysis sensitivity is not available in these techniques. For example, the patent document 3 discusses a technique for analyzing a photoresist developer in order to carry out an analysis with higher sensitivity. In this technique, vaporizing a sample in a sample vessel, the main components are eliminated, and also contaminations are condensed. The condensed contaminations are analyzed by an inductively-coupled plasma mass spectrometry. However, in this method, the use of a microwave as a heating source makes the apparatus structure complicated.
Further, in case that a plurality of sample vessels to be measured are arranged in the chamber at once, the pipe arrangements for supplying an inert gas to each sample vessel become complicated, too. Thus, this method is inconvenient for measuring many samples concurrently.
[Prior Art Documents]
[Patent Documents]
    [Patent Document 1] Japanese Patent Application Laid-Open No. 2-13834    [Patent Document 2] Japanese Patent Application Laid-Open No. 3-172759    [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-5799